I don't know how this functionality was lost in my setup, I've looked everywhere in config to re-enable it and cannot find it!
HOW do I enable that I can drag a lister (independent) window on another lister window and make them into a single double-lister window?
Also, since we are at it, even if you tell me how to (re-)enable it, can someone also tell me how to CONSISTENTLY successfully do this "snap-into"? I mean even when it was enabled, I managed to do it like 8 in 10 times, but sometimes it just didn't snap. Is there a specific point to grab the window from and a specific place in destination window (Ithink on its right side?), to always work?
Dragging tabs between tab bars is the most generic way to move folders around panels/windows. There are also further options in the right-click menu for tabs.
The mode you're thinking of is probably:
Preferences / Location Bar / Toolbars / Allow docking of Listers
But that requires using the (very) old-style "static" file display border without the toolbar which would normally be there, while doing it via tabs always works.
Commands that work on toolbars or hotkeys can also join windows together in various ways, as another alternative.
That is probably the problem. That I am not using the old style toolbar.
Your solution of moving tabs, does not CREATE a double pane window from a single pane one.
It has to already be double pane before moving a tab to the right pane.
This is different than the functionality I wanted (make a single pane window, into a double pane, just by dragging a lister to the right side of another lister).
Not sure why the separate control bar, prohibits docking.